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                            [Illustration:

                               MACHINES
                               _AT WORK_


                              MARY ELTING
                           _ILLUSTRATED BY_
                              LASZLO ROTH]

                            [Illustration]

           Copyright 1953 by Duenewald Printing Corporation.
             Lithographed in the United States of America.




                           MACHINES AT WORK

                            [Illustration]

                            [Illustration]




                               MACHINES
                                AT WORK

                           _By Mary Elting_

                            [Illustration]

                            ILLUSTRATED BY
                              LASZLO ROTH

                 GARDEN CITY BOOKS GARDEN CITY, N. Y.

                            [Illustration]

                            [Illustration]


MAN-MADE GIANTS

You could do everything that the machines in this book do. For some of
the jobs, of course, you’d have to get friends to help you. But people
have always been able to work and build wonderful things, using just
their muscles. And they can do a very great deal more when they use
their brains, too. They can invent machines to make work thousands of
times easier and faster.

The big machine in the picture is a shovel that’s used for digging an
enormous hole. In one bite, its scoop can tear out a chunk of earth more
than twice as tall as a man. Its long arm, called the boom, lifts the
load as high as the top of a seven story building, then swings around
and drops it almost a city block away.

There are only a few shovels like this in the world. They were
especially made to work where beds of coal lie close to the surface of
the earth, covered by a layer of soil. The shovels clear away the soil
so that other machines can dig out the coal.

[Illustration]

When a giant shovel has cleared off one spot, its crawlers begin to
turn, and it creeps slowly ahead. But it can’t travel on roads. It’s far
too big and heavy and tall--so big, in fact, that it came to the mine in
separate pieces. Forty-five freight cars were needed to haul all the
parts for just one machine from the factory to the mine. Then experts
put the parts together right where the shovel was to start digging.

And dig it does. In one minute its scoop can bite out as much dirt as
3,600 men could dig just using their muscles to lift ordinary hand
shovels!

The giant shovel is one of the biggest machines ever made, but there’s
another that can lift even bulkier things. It is an overhead crane that
works in a shipyard.

Often the crane hoists big boilers out of ships so that repair men can
work on them. It is so huge that it carries another crane on its back.
The piggy-back crane--that’s its real name--reaches down and lifts
things off the deck of the ship, too.

[Illustration: strongman]

Hammering is another kind of muscle work that

[Illustration: crane]

machines can do quickly and easily. Suppose the water pipes under your
street need mending. Repair men have to tear up the pavement in order to
reach the pipes. So they bring in jack hammers to do the pounding.
Strong blasts of air run the hammers, and, in no time, the pavement is
broken up.

[Illustration: rock crusher]

Crushed rock was used for making the paved street in the first place. It
came from a big machine called a rock crusher, which breaks up chunks of
stone into small pieces. Strong jaws inside the crusher chew at the
stone until they have made it into bits that are just the right size.

[Illustration: pile driver]

An even bigger pounding machine is the pile driver. It can hammer a
great thick log down into the ground almost as easily as a man can
hammer a nail through a board. One kind of pile driver does its pounding
job with a steam piston. Another kind lifts a heavy weight and lets it
bang down on top of the log, called a pile. The one in the picture
works in a harbor. It drives piles deep into the earth that lies under
water. A whole group of piles make the foundation for a pier in the
harbor, for ships to tie up alongside.

Harbors and rivers must be kept safe for ships. If mud and sand pile up
in a thick layer on the bottom, ships may get stuck. So dredges go to
work clearing the mud and sand away. Often a clean-up job takes a long
time. The men who run the machinery live on board the dredge, just as
sailors live on a ship.

[Illustration: dredge]

Some dredges have scoops that dig under water. Others, like the one in
the picture, use giant suction pumps. The mud or sand they suck up is
called spoil.

If there’s hard-caked mud on the bottom, cutter heads break it up. Then
it’s ready to be pumped out through huge steel pipes that stretch away
from the dredge like a great snake and pour the spoil out on land.

Of course, a dredge must stay in one place while it is working. So it
carries along two huge spikes called spuds. These move straight up and
down at the stern of the dredge. When they ram into the earth
underwater, they keep the dredge from drifting.

[Illustration: dredge]

A spud is so heavy that it pokes its own hole in the muddy bottom of a
river or harbor. But making holes on dry land is a different problem.
For instance, you can’t just poke a telephone pole into the hard
ground, or pound it in easily with a pile driver, either. So, in many
places, a machine bores holes for telephone poles, just the way a
carpenter bores a hole with a brace and bit. Then the machine’s long
arms reach out, lift a pole into the air and plug it down neatly into
place.

[Illustration: borer]

Long ago our ancestors discovered how to use simple tools--such as
hammers, shovels, crowbars and rollers. These things seem very ordinary
to us, but they were really wonderful discoveries. The clever men who
invented them were providing ideas, one by one, which scientists and
engineers used much later. Our great machines are combinations of many,
many things that men discovered from using simple tools.


POWERFUL PUSHERS

The giant shovel digs; the overhead crane lifts; the pile driver pounds.
All machines multiply the power that’s in the muscles of men--or of
animals. The pushingest animal is an elephant. In some places in the
world, elephants are trained to clear land by putting their foreheads
against a tree and heaving until the tree topples over.

A tree-dozer can out-push an elephant. The one in the picture has a
special forehead built in front. With a slow, steady shove, it clears
the way for roads or opens up fields for farms.

[Illustration: tree-dozer]

Farmers used to dig their fields by hand. Then they hitched horses to
plows. Now a tractor does the work, but we still measure its strength in
horsepower.

[Illustration: elephant]


MACHINES FOR FARMERS

Dan is a farmer. He knows how to use almost any kind of farm machine,
and he has lots of them. The most important is his tractor, for it is
busy all year round. Sometimes it pushes. Sometimes it pulls. Or it may
stand still and lend its power to other machinery.

When the frost is out of the soil in the spring, Dan backs his tractor
into the tool shed and bolts on a plow. This one is a two-gang plow--it
can make two furrows in the earth at the same time. Dan touches a lever.
The blades of the plow lift up so they can’t dig into the farmyard and
the road, and Dan chugs off to the field. Another touch on the lever
sends the blades down. In a few minutes, Dan has made the first furrows
across the field.

Now he has to turn. He lifts the plow and steps on the left brake pedal.
While the big left wheel stands still, the right one keeps going and
turns the tractor, ready to start the next furrows. When Dan wants to
stop, he steps on both the left and right brake pedals at once.

After plowing comes harrowing. The tractor pulls a different implement
for this job--a whole row of saucer-shaped metal discs that chew up the
soil and spread it out evenly. Now Dan is ready to plant corn.

[Illustration: harrowing disc]

[Illustration: corn planter rear]

The corn planter does five jobs in one trip down the field. It makes
trenches for two rows of corn. It drops corn seeds into the trenches. It
drops fertilizer alongside to give food to the young plants. It covers
the seeds. And it leaves a mark all along the field to show exactly
where the tractor should go to plant the next row of seeds. Dan follows
the mark very carefully. All the rows must be exactly the same distance
apart, because the tractor will have to go through the field again to
cut out the weeds after the corn starts to grow. If the rows are badly
spaced, the tractor wheels will squash some of the plants.

[Illustration: corn planter side]

[Illustration: cultivator]

When Dan was a little boy, he used to help his father hoe the corn by
hand, getting rid of weeds and loosening the soil. Now he has an
implement called a cultivator which does the job.

After the corn is well up, Dan pulls the cultivator through the field,
driving carefully, with the wheels between the rows. Small blades on the
cultivator cut through the weeds and break the soil into loose chunks.
The pictures show several kinds of cultivator blades.

All summer long the corn grows tall. Dan waits till the ears are dry
before he harvests them, ready for his cows and chickens to eat in
winter.

[Illustration: hand tools?]

Dan’s farm is small, so he can’t afford to buy a big corn-picking
machine. But his neighbor Al has one that he rents out, and one morning
Dan drives it to his cornfield. His tractor seems lost inside the
picking machine. Gatherers that look like the pointed snouts of huge
mice creep along in front of the tractor close to the ground. One by one
the stalks of corn go into the machine, which snaps the ears off. Then
revolving claws and rubber paddles rip off the husks, and an elevator
carries the clean ears back to a wagon which the tractor pulls along. In
a very short time, Dan’s whole field is done.

Corn isn’t the only thing that grows on Dan’s farm. He raises tomatoes
for the market, too. At planting time, he needs two helpers who ride on
little seats very close to the ground behind the tractor. They put the
tender little tomato plants one by one into a trench which the planting
machine digs, and then a special wheel covers the roots with earth.

Dan has some wheat fields, too. In the spring, after the ground is
harrowed, a wide planting machine sows many rows of wheat at a time. And
it drops out fertilizer to feed the plants on the same trip.

[Illustration: cornfield]

Many farmers use their tractors for harvesting wheat, but Dan doesn’t.
Instead, he rents a shiny red reaper which he calls a “package job,”
because it moves itself along and does the whole harvesting at once. It
cuts the wheat, shakes the grain loose from the stalk and separates it
from the husks. If there are weeds growing in the wheat, the machine
separates the weed seeds from the wheat kernels and spills them into
different bags.

[Illustration]

Dan sits high in the air at the front of the machine. He says he has a
“box seat.” Behind him on a bench sits a helper who ties the bags as
they fill up and puts new bags in place. Dan says it won’t be long
before somebody invents a machine that will reap the wheat, grind the
flour and bake bread right there in the field!

All of Dan’s machines are wonderful inventions, but they can be
dangerous, too, if people are careless. To give himself and his helpers
warning, he has painted bright stripes and markers around open places
where fingers might get caught in moving parts.


EGGS, TOO

Dan has a flock of fine white Leghorn chickens. He takes care of them by
machinery, for eggs are a crop, too. The hens live in cages with wire
floors, so that they keep very clean. All their droppings go through the
wire to a platform below. With a special scoop, run by his tractor, Dan
cleans the manure from the platform and puts it in a pile to be used as
fertilizer on the fields.

Every day the chickens have their meals brought to them on a moving
belt. The eggs they lay drop through their nests onto another belt that
carries them away. Finally a machine sorts the eggs according to size,
ready for packing.

Some farmers raise chickens for the market. Of course, the feathers must
be taken off after the chickens have been killed. There are machines for
this, too. One kind has mechanical fingers that pluck the feathers as
chickens go past on a moving belt.

[Illustration]


MACHINES FOR BIGGER FARMS

Dan’s neighbor Al has a big dairy farm, with lots of cows to milk every
day, and land enough to grow their feed. Besides his corn picker, Al has
other special machines. One of them cuts corn while it is still green,
chops it up fine and loads it into a truck. The truck has a sort of cage
over it to keep the corn from spilling out. Next, Al turns his tractor
into a stationary engine which runs a blowing machine. A wide belt from
a pulley on the tractor turns the blower, which shoots the chopped-up
corn to the top of a storage tower called a silo. The green stuff
ferments in the silo and turns into wonderful food for the cows.

Al’s fields are so big that he needs larger plows than the one Dan uses.
He hires an airplane to spread dust that kills plant-eating insects.

Al plants his hayfields with a seeding machine that he pulls behind the
tractor. Grass seed is so tiny that it can’t be planted deep. Al’s
seeder sprinkles just the right amount of seed on the soil, and then
squeezes a thin covering of earth on top. He says the machine “tucks
each seed to bed.”

[Illustration]

After the mowing machine has cut the hay, Al pulls his automatic baler
across the field. The baler scoops the hay up, then presses it into a
box-shaped bundle, slices it off neat and square, and ties it with
strong twine. One by one the bales drop out on the field, ready for a
truck to pick them up.

Some farmers rake their hay into long heaps called windrows before they
bale it. The machine that does this job has many teeth that whirl round
and push the hay sidewise into the windrows. The whole field has a
rolling look, like ocean waves.

The hay must be dry before it goes into the barn. If it isn’t, it may
get moldy. And green hay may even be dangerous. It can actually make
heat enough to start a fire.

[Illustration]

To be sure his hay keeps well, Al has a blower that circulates air
around the barn and dries the bales completely.

[Illustration]

Some farmers use machines that tie the hay into round bales. Others
don’t bale it at all. They use stackers to pile it into tall stacks
where it is kept till the cows are ready to eat it.

[Illustration]

The stacker fits onto the tractor. When it was first invented, farmers
thought it was a sort of luxury, because it was used so seldom. Then
they discovered that they could put it to work on other jobs, too. If a
platform of boards is fitted across the forks of the stacker, it turns
into an elevator that a man can stand on. Then he can paint the barn or
pick apples from high branches without having to climb up and down
ladders.


MILKING MACHINES

It would take a lot of work to milk all of Al’s cows. So he uses milking
machines. When a man milks a cow, he squeezes with his fingers. Instead
of fingers, the milking machine has four soft rubber funnels that fit
over the cow’s teats. A pump squeezes the funnels, presses the milk out
and sends it through hoses to the milk can.

A farmer has only two hands. His milking machine has four funnels with
hoses. So it can work much faster, and he can have several machines
going at once.

[Illustration]

You’d never guess it, but a cow is a nervous, fussy animal. She lets
down her milk easily if the same person or the same machine squeezes on
her teats with the same rhythm every day, but any kind of change or
hurry upsets her. Then she’s hard to milk. And so Al’s machine is built
with a very accurate timer which makes the funnels squeeze exactly
forty-eight times a minute.

A good farmer tries to make life calm and comfortable for his cows. Even
the names for some things in Al’s barn have a comfortable sound. The
place where the cows wait to be milked is called the loafing pen. The
room where they stand for milking is kept perfectly clean, and it’s
called the milking parlor.

Before the machine is attached, the cows’ udders and teats must be
washed clean. Al has fixed an upside-down shower bath for his cows. He
built a concrete pen with sprays coming up through the floor. The
showers clean the cows and make them feel so calm that he never has any
trouble milking them.

The fanciest milking parlor of all has a machine in it called a
Rotolactor. It is really a quiet, slow merry-go-round. Cows amble up a
ramp and step into stalls on the gently moving platform. A man attaches
milking machines to them, one after the other. By the time each cow has
been carried halfway around the big circle, her milk has been pumped out
into a glass tank that sits on a rack above her. A man takes off the
rubber cups, a

[Illustration]

gate opens in front of the cow, and she steps off onto another ramp that
goes from the center of the merry-go-round, underneath it and out to the
barnyard. Twenty-five cows at a time can be milked on the Rotolactor.

[Illustration]

Automatic gadgets empty the milk from the glass tanks, wash them,
sterilize them and get them ready for the next round. All the time men
are busy keeping the stalls clean and tending to the machinery. Most
dairies milk the cows twice a day, but the Rotolactor milks three times.


MACHINES FOR EVERY JOB

The Rotolactor was invented for one particular kind of huge dairy. But
farmers everywhere like to have good machinery to do special jobs.

For hilly country, there’s a plow that has one of its blades higher than
the other so it can work on a slope. There are chisel plows that dig up
hard soil by clawing at it with strong steel fingers.

One farmer in Texas decided to make his tractor do the plowing all by
itself, after he had driven it once around the field to give it a start.
He invented a guide

[Illustration]

[Illustration]

wheel that went ahead of the tractor in the furrow he had made. Now the
guide led the tractor around in a spiral that got narrower and narrower
until at last it stopped in the center of the plowed field. Another

[Illustration]

Texan, with a bigger field and more machines, had a larger idea. He set
three tractors loose without drivers, one behind the other. Away they
went, round and round. If one traveled too fast and caught up with the
one ahead, they stopped. The only work he had to do was go out and start
them up again!

There have even been experiments in guiding plows by remote control
radio, the way airplanes can be guided. The farmer just sits under a
tree and pushes buttons in a control box.


COTTON MEANS HARD WORK

[Illustration]

Cotton is a crop that has always taken an enormous amount of work. Even
after cultivating machines were invented, men had to go through the
fields twice every year and hoe out weeds around the plants by hand. One
farmer rigged up a contraption that made hoeing easier. He hitched an
air compressor to his tractor and ran hoses from the compressor to four
special hoes. Then the escaping air jiggled the hoes in the men’s hands
and saved the work of swinging them up and down.

[Illustration]

Nowadays some of the big cotton farmers have an easier way of solving
the problem. They just keep the weeds from growing in the first place.
As the planting machine drops the cotton seeds, it spreads weed killer
along each side of the row. This killer is a particular kind of chemical
that keeps the weeds from sprouting, but it does not hurt the cotton.
The only weeds that grow in the field come up between rows where it’s
easy for a cultivator to scratch them under.

At cotton picking time, machines now do the work in many places. Cotton
is ready to pick when the little round heads of white fluff called bolls
break open. Not all the bolls on one plant burst at the same time. A man
who picks by hand can tell by looking which ones are ready. Of course
the machine doesn’t have eyes, but its tiny barbed steel fingers catch
up only the opened bolls. The fingers are fixed on a turning drum. They
pluck the cotton from the plant, carry it around to be pulled off and
blown through a big pipe into a large basket behind the driver.

People have been trying for at least a hundred years to invent a perfect
cotton picker, and they haven’t succeeded yet. The machines still can’t
do as careful a job as skilled men and women can do by hand.


SPRAYING MACHINES

Nobody could possibly do by hand all of the spraying that protects
farmers’ crops. Mechanical sprayers come in many shapes and sizes. The
most usual sort for big fields travels along behind a tractor, shooting
chemicals out from nozzles in a pipe that is twenty or thirty or even
sixty feet wide.

Some of the special sprayers are queer looking machines. One of them has
six squirmy arms, bent in different directions so that they get the
chemicals underneath leaves and on top as well. The kind that sprays
fruit trees pumps chemicals out of twelve pipes at once. It works so
hard and fast that farmers call it a cyclone.

[Illustration]

Then there is a sprayer that can be used for several different kinds of
job. One day the farmer hitches it up to a tank near cattle pens. As the
cattle walk down a narrow path between two fences, he sprays them with a
chemical that kills bothersome insects. Next day, he may want to paint
his fence. So he rigs the machine up differently and shoots paint onto
the boards.


HOME WORK

All of this sounds as if everything that a farmer could need must have
been invented by now. The fact is that there are new inventions coming
along all the time, and farmers themselves make many of them. Every day
in the week some farmer is likely to think up something he needs, then
go to work making it. Here is a sample:

[Illustration]

Many farmers specialize in raising a kind of corn called hybrid corn. In
order to make it grow properly, they must pick the tassels off the tops
of some of the corn plants. Each tassel has to be picked by hand, and
it’s a slow job in a big field. So one farmer rigged up a machine that
gives four tassel-pickers a comfortable ride all at the same time, and
it gets the job done much more than four times as fast as before.

[Illustration]


WONDERFUL INVENTIONS

It would take a whole book just to list the other machines that help
different kinds of farmers. But here are some that are fun to know
about:

One clever contraption attached to a tractor grabs hold of nut trees and
gives them a hard shaking. The nuts fall on the ground, ready for a kind
of giant vacuum sweeper to come and suck them into a truck.

Crops that grow underneath the earth need their own sort of harvesting
machine. There are potato diggers and many others. The sugar beet digger
works in a particularly clever way. Machine fingers feel for the beet
tops. They set off a knife which cuts the tops off while other fingers
lift the beet out and put it on an elevator which removes the clods of
dirt as it travels. Once in a while the machine makes a mistake and
delivers a stone, or a chunk of mud at the end of the elevator. Men do
nothing but throw the junk away and let the beets slide into the truck
that travels alongside.

[Illustration]

A farmer always has to keep an eye on what his implements are doing,
unless he has a helper who rides along on machines like this big reaper.
When the tractor

[Illustration]

pulls a cultivator or a planter, the driver must turn his head often to
see how the work is going. For a long time, farmers complained that this
was a pain in the neck, and they really meant that their necks hurt from
turning so much. Some of them actually went back to using horses,
because they could either walk or sit behind horse-drawn machines. So
the farm machine makers had to change as many of the machines as they
could, placing them beside the tractor or out in front where the driver
can watch what is going on.

Tractors themselves come in many sizes and shapes. Some are built very
high off the ground so they can pass over tall crops without hurting the
plants. Some have four wheels that can be pushed close together for work
in one field and pulled wide apart for work in another. Some have three
wheels.

Mostly, farmers buy tractors the way people buy automobiles. They pick a
model they happen to like and then argue that it’s the best in the
world. Of course, a little light “cub” tractor is easier to handle than
a big one, but it can’t do the hard work of a heavy model with huge rear
wheels and tires. And here’s something about the tires--farmers often
fill them with water instead of air to give them more weight when they
grip the ground. In winter, these farmers must put antifreeze not only
in the radiator but in the tires as well!

[Illustration]

On enormous farms where very heavy work must be done, there are often
crawler tractors to do it. Instead of tires they have caterpillar treads
that give a better grip on the ground. Then they can pull a whole string
of plows the way you see them in the picture, staggered out behind.

This kind of tractor was first named caterpillar by only one
manufacturer. But people liked the idea, and they began to call all
crawlers caterpillars.

A caterpillar is powerful enough to push a snow plow, too. Or it can
bulldoze out a hole for a watering pond or a cellar for a new building.


BUILDING MACHINES

Charlie is the man who can tell you about driving a caterpillar tractor.
He works in a city, helping to put up big buildings, and he knows how to
use other construction machines, too. In fact, Charlie grew up with
machines, for his father and his uncles and his grandfather were
construction workers. It often happens that families pass along their
knowledge of building from the older to the younger men, and they are
very proud of their skills. Charlie uses the caterpillar tractor with a
bulldozer blade to push heaps of earth and rock into a pile, ready for
the shovel to load on a truck.

[Illustration]

[Illustration]

[Illustration]

People often call the shovel a “steam shovel,” but that’s not its right
name. You hardly ever see a real steam shovel any more. Years ago the
big digging machines were driven by regular steam engines. Before they
could start to work on a job, the men had to build a fire in the boiler
and wait until they had enough steam pressure to make the shovel go. Of
course, this wasted a lot of time. So, when very strong gasoline and
Diesel engines came along, builders began using them for their shovels
instead of steam engines.

Many shovels and other construction machines ride to work on long
gooseneck trailers. They travel faster that way than they could on their
own crawlers. And, in cities, the caterpillar treads might damage the
pavement. To load and unload a shovel, the operator sets a short ramp of
heavy planks against the trailer. Then the shovel creeps up and down on
its own crawlers.

The kind of shovel that’s used on a job depends upon the work that must
be done. If a basement has to be dug through hard rocky earth, Charlie
may operate a crowd shovel, which crawls down into the hole. The shovel
has a heavy dipper with teeth along the rim. When it digs, it crowds its
teeth down into the ground. Charlie, sitting inside the cab, called the
house, swings the dipper outward and up, then dumps the load into a
truck.

[Illustration]

Another shovel digs in the opposite way. It’s called a pull shovel. The
teeth dig down and toward the driver. It can work from a bank and
doesn’t have to go down inside the hole at all.

Sometimes Charlie uses a crane to get loose earth out of a hole. The
crane has a long boom with wheels at the tip. Cables run over the
wheels. Charlie fastens a kind of bucket called a clamshell to the
cables. With its mouth open, the clamshell drops down over a heap of
rocks and earth. Then Charlie starts machinery that pulls up on the
cable. The jaws of the clamshell squeeze together and come up with a
load of earth. Now Charlie swings the whole crane around till the
clamshell is hanging above a truck. He pulls a cable that opens the
bucket, and the earth and stone tumble out.

After the basement for a building has been dug, Charlie uses the crane
for other jobs. Men hook the cables to heavy steel beams, and Charlie
lifts them into position.

[Illustration]

No matter what he is doing, he has a lot to watch out for. He must know
which of four brake pedals to use at any moment and which of four hand
levers to pull. One lever works the turntable which swings the whole
house around. One moves the boom up and down. The other two control the
cables.

[Illustration]

At the same time, Charlie must watch what’s going on outside. A man
stands on the job giving signals. Thumbs up mean “Take the boom up.”
Thumbs down mean “Lower the boom.” When the signal man points up with
his first finger, it means “Raise the cable.” If he wiggles the finger,
it means “faster.” When Charlie is lifting a beam and has to hold it for
a while in the air, he says he “takes a strain and dogs it off.” Dogging
is his word for setting the brake on the cable.

Things are always likely to fall around a construction job, so the men
who work on the ground have steel caps in their shoes to protect their
toes. They wear steel helmets on their heads, too!

As the building goes up, Charlie’s crane lifts loads higher and higher.
After a while he has to put a jib on the boom. This is an extension that
makes it longer. When the building goes too high for his crane to reach,
Charlie works another crane. It sits on top of the building’s framework
and reaches down from there.

[Illustration]

After Charlie lifts a big steel girder into position, other men bolt it
in place then fasten it tight with rivets. A man called a heater gets
the rivets red-hot in a fire. Using tongs, he tosses them one at a time
to the catcher who reaches for them--not with a mitt but with a kind of
cup. The catcher pokes a rivet in a hole, and two other men fasten it
tight. One of them, the bucker, holds the rivet in position with a bar,
and the rivet man pounds the other end flat with a rivet gun. (The gun
works like a jack hammer, and it makes an awful racket.)

When you’re down in the street, it’s hard to realize that there may be a
heavy wind blowing across the bare girders of a tall new building. High
in the air, men have to keep their balance on narrow places and walk
with sure feet. There are families who specialize in work far above the
solid ground. Boys learn from their fathers how to walk safely without
being afraid--although almost everyone is frightened at first. And, of
course, everyone is careful. In New York a group of Mohawk Indians have
worked on many high buildings where men like Charlie did the beginning
work.

[Illustration]

[Illustration]

Once in a while Charlie helps to wreck an old building before putting up
a new one. First, a crew of men go in and take away everything that can
be used again or sold for junk. With specially made crowbars, they pry
away floors and door frames. They take out furnaces and plumbing
fixtures. Then Charlie gets to work with his crane. At the end of a
cable he fastens a heavy steel ball, called a skull cracker. Then,

[Illustration]

swinging the boom, he bashes the skull cracker into the wall of the old
building. Over and over, the ball strikes the mortar and bricks. Cracks
spread, and big chunks of the wall start tumbling to the ground. In a
little while Charlie and his machine have made a heap of rubble out of a
house that it took dozens of men to put up.


BUILDING A ROAD

[Illustration]

Once Charlie worked on a road-building job. There he used a crane and a
shovel and many other machines besides. This particular road had to
cross a big swamp near the ocean. So the first problem was to fill up
the swamp with something solid. In order to get enough earth and rock
for the fill, men would have had to tear down a whole mountain. Instead
they called in suction dredge machinery for the job. The huge pumps
sucked sand from the bottom of the sea and poured it through pipes onto
the swampy ground. When the water drained away, millions of tons of fine
white sand were left.

[Illustration]

Charlie helped level the sand off with a bulldozer. Then he moved on to
a place where a hilly spot had to be leveled. There he drove a carrying
scraper, a machine with a scoop between its front wheels and its rear
wheels. The sharp scoop scraped up a load of earth, and Charlie drove
off to dump it in a low spot. When he got there, a pusher blade at the
back of the scoop pushed the earth out. Round and round he went,
without having to stop for loading or unloading.

Other men used a different machine like the one in the picture. This
earth mover carried more in one load than the motor scraper, and it was
better for hauling earth longer distances. For very short hauls, Charlie
drove a fast little tractor. At least it looked small compared to the
giant machines. It pushed a scoop in front of it like a shovel, then
lifted a load, turned swiftly and dumped the earth where it was needed a
few yards away.

Charlie’s road was going to be a special highway for speedy traffic. In
order to make it as safe as possible, the crossroads had to be lifted up
over the new highway. Crews of men built these overpasses. First they
used the huge earth-moving machines to make little hills on each side of
the highway. Then they built bridges of concrete and steel between the
hills.

At one place, there were two houses on the exact spot where the hill for
an overpass had to be made. Instead of tearing the houses down, moving
men just carried them away with the furniture still inside. First they
raised the houses off the ground with jacks. Next a tractor backed a
wide, low trailer up close to each house. Using special machinery and
rollers, the men

[Illustration]

eased the whole building onto the trailers. That same night, the houses
were set down on new foundations, and the people went right on living in
them.

At one place, a big ledge of rock was in the way of the new road. Men
called powder monkeys blasted the ledge to smithereens with explosive.
Then Charlie came in with his caterpillar tractor and a rock rake.
Unlike a garden rake, which you pull, Charlie’s rock rake scratched up
rocks and pushed them ahead of it. He shoved all the loose chunks of
stone away, but several big ones were too far underground for the rake
to pry them loose. So Charlie put a ripper on behind his tractor.

[Illustration]

[Illustration]

The ripper had strong prongs that could dig down deep and get a good
hold on a boulder. The frame that held the prongs was hollow. For very
heavy work, Charlie filled the hollow frame with sand to give it a lot
of weight so the prongs wouldn’t slip. To pry out the very largest
boulders, Charlie sometimes got another driver to hitch his caterpillar
onto the ripper. Then the two tractors, chugging together, did the job.

After the bulldozers and scrapers and rakes had built a rough bed for
the highway, Charlie helped to smooth it down and get it all ready for
finishing. He used a long six-wheel motor grader for the job.

The motor grader had its Diesel engine in the rear, above the four
wheels that did the pushing. The guiding wheels were way off at the
front, and in between was the scraping blade, placed where Charlie could
watch it.

Charlie could set the blade at almost any angle, just as a barber can
tilt a long-bladed razor. And Charlie was proud of the way he had left
the road almost as smooth as a barber leaves a man’s face.

[Illustration]

Charlie could play tricks with the motor grader’s front wheels, too.
Besides steering them in the ordinary way, he often made them lean over
toward the right or the left. To look at them, you’d think they were
broken, but they were only tilting to do a special job. They were
actually in a tug-of-war with the blade and the earth it was pushing.
The weight of the earth against the blade pulled the grader toward one
side. But the leaning of the wheels pulled in the opposite direction. So
the two pulls balanced each other. Charlie could guide the grader in a
straight line without having a wrestling match with his steering wheel.

[Illustration]

Charlie leaned his wheels when the grader went around a bend in the
road, too. They helped the long machine to turn easily. If he had to
back into a ditch,

[Illustration]

[Illustration]

he didn’t worry. The great wheels adjusted themselves to the sloping
earth. All six wheels stayed on the ground, and the machine never got
hung up the way a four-wheeled automobile would.

[Illustration]

When the earth had been smoothed down, it was time to put the hard
surface on. Trucks brought in crushed rock to make a solid bed. Concrete
mixers covered the rock with concrete. And asphalt spreaders put a coat
of asphalt on top.

Wherever the asphalt wasn’t spread evenly, men with rakes finished the
job by hand. Then came the tandem roller to pack it down and make the
surface smooth.

A Diesel engine moved the roller’s great weight quickly back and forth
over the asphalt. In no time the road was as smooth as a table top. If
the driver wanted to, he could turn his seat sideways. Then he could
easily see whether he was guiding the roller straight forward and
straight back.

[Illustration]

Many people call road rollers “steam rollers.” That’s because the first
ones really were driven by steam engines. Men have a lot less fuss and
bother with a modern Diesel-engined tandem. There’s no need to start the
fire or shovel coal to keep steam up. You can still see some steam
rollers at work, though, because they are strong machines that last a
long time. But when one wears out, it is replaced with a modern roller.

After the roller finished smoothing all the asphalt down, Charlie’s road
was ready for traffic, but the job still wasn’t quite done. All along
the highway the machines had left bare banks of earth. These had to be
protected from the weather--just the way a house is protected with a
coat of paint. The best coat for the earth is grass of one kind or
another. So Charlie turned gardener. In some places he used the motor
grader again to prepare the soil so that seed could be planted. With the
blade of his grader hung away out at the side and pointed up in the air,
he smoothed off the steep banks. Running along the edge of the road, he
filled in the soft shoulders.

[Illustration]

Then a seed-planter sowed the grass. And finally Charlie used the
strangest machine of all. It chugged and puffed and spit out great
mouthfuls of hay, which fell over the newly-planted grass! The hay
protected the grass seed and kept it moist until its roots were growing
strongly in the soil.


MORE ROAD WORK

The road was finished now, but some of the machines still had work ahead
of them. In fact, road work is never ended.

All summer long, tractors pull mowing machines beside the highways,
cutting the grass. Brush and small trees must be kept cleared away so
that drivers can see ahead. In winter, the motor graders and the snow
plows can keep the road clear. But in places where heavy snow piles up
into drifts, caterpillar tractors often push special snow plows that eat
through the drifts with powerful whirling blades. With one motion these
plows dig out the snow and throw it off to one side of the road.

[Illustration]

The caterpillar treads work better in snow than wheels with tires. So
the “cats” are used all winter long in the Far North. There they even
pull whole trailer trains on runners. The one in the picture is hauling
Muskeg schooners, which are really trailer houses on sleds. Muskeg is an
Indian word for swamp. The cats pull the schooners over frozen,
snow-covered swamps.

You may wonder why anyone wants to use a trailer home in the roadless
wastes of the Far North. The fact is that men work there the year round,
prospecting for oil. When they think they have located oil there or
anywhere else, well-drilling machinery goes to work.


DRILLING MACHINES

Everybody knows that oil wells and derricks go together. The tall
derrick towers are needed to hoist drilling equipment in and out of the
hole.

[Illustration]

When men start to drill a well, they fasten a cutting tool, called a
bit, to a piece of pipe which hangs upright in the derrick. Machinery
turns the whole thing round and round, so that the bit grinds down into
the earth. When one length of pipe, called a joint, has almost
disappeared into the hole, men screw another joint onto the top of it.
Now the engine turns the double-length pipe, and the bit digs down
deeper.

Men, working on the floor and high up in the derrick, hoist more and
more joints into position and screw them together as the bit goes on
down. After a while, the bit gets dull. A new one must be put on. So,
strong cables that run over wheels at the top of the derrick begin
lifting the whole string of pipe out. Joint by joint, they unscrew the
pipe and stack it out of the way. When the last joint comes up, men
change the bit. Then back the pipe goes, joint after joint, into the
hole.

Wells must often be drilled more than two miles deep before the bit
breaks through into an underground reservoir of oil. That means that the
string of drilling pipe must be two miles long. The machines that help
to handle it are very strong, but on many rigs, men have to use their
own muscles a great deal, too.

For deep drilling, the most modern rigs have a lot of fine new
machinery. Automatic tongs take a tight grip on the drilling pipe when
it is being unscrewed. Men used to work the tongs by hand. Mechanical
hands

[Illustration]

now keep the bottom joints from dropping back into the hole, and arms
high up in the derrick do the job of stacking the pipe.

The skillful men who work with the pipes and the machinery call
themselves roughnecks. The driller is the one who actually controls the
drilling pipe. He never says he is digging a well. He says he is “making
hole.”

[Illustration]

Almost all deep wells are now drilled by the turning pipe and bit, which
are called a rotary rig. But sometimes you can see an old-fashioned
cable rig at work. It makes hole with a bit that pounds its way down
into earth and rock. A cable raises the bit, and then lets it fall down
with a bang that chips away a hole. On both kinds of rig, the hole is
cleaned out with water. The water turns the rock dust into mud, which is
then pumped out.

The cable rig idea is about two thousand years old! That long ago
Chinese drillers made water wells, salt wells and even oil wells. The
picture shows what one of these ancient rigs was like.

Look first of all at the long board attached to the rope that goes up
over a roller and down into the well. Then look at the platform behind
the board. Men jumped from this platform down onto the board. That
jerked on the rope and pulled the drilling bit up in the well hole. When
a man jumped off the board, the bit fell down and chipped away some
rock. Round and round a whole crew of men raced, jumping onto the board
and climbing back onto the platform as fast as they could. Still it took
a long time to drill a well--sometimes as long as ten years.

[Illustration]

Now look at the big wheel turned by a bull at the right. This wheel
lifted the pipe made of hollow bamboo that you see at the left. The
pipe was actually a bailer. Every once in a while the men poured water
into the hole, let the bailer down and hauled up mud. Then the bit could
go on drilling. Oil workers today still call the wheel which winds up
cable “the bull wheel.”


PIPELINE MACHINES

When a well brings in oil, a new group of men and machines go to work.
They lay a pipeline, through which the oil can be pumped to factories
called refineries. Some pipelines are hundreds of miles long.

After surveyors have decided just where the line should go, bulldozers
clear away brush, push over trees, heave big boulders to one side,
making a wide pathway across country. In many places, the pathway is
good enough for trucks to follow. They bring in lengths of pipe and lay
them down end to end. Where the going is rough, a caterpillar tractor
carries the pipe, one length at a time, hanging from a side-boom.

Now welding crews go to work fastening the ends of the pipe-lengths
together. When they have finished, the “hot-dope gang” comes along. They
are men who cover the pipe with a wrapping and then with a hot asphalt
mixture to protect the metal.

Meantime, a wonderful machine called a trencher has been at work. This
is a cat attached to a rig which

[Illustration]

[Illustration]

looks very much like an old-fashioned water wheel. Each bucket on the
wheel has steel teeth. The cat turns the wheel and pulls it forward. The
buckets scoop up earth, and spill it out onto a belt that dumps it in a
heap at one side. The trencher plugs ahead, uphill and down, digging a
ditch just the right width and depth.

Following behind the trencher, cats with booms hoist up the snaky
pipeline and ease it over into the trench. Finally, bulldozers backfill
the trench. That is, they cover the pipe with the dirt that the trencher
left alongside. On one job, the men had to work at top speed in the
desert and in rocky, mountainous country. They were all so glad they’d
finally succeeded in getting the pipeline built that they put on a
celebration. Whooping and hollering, they tossed their sweat-stained
hats into the trench in front of the bulldozer as it backfilled the last
few feet of earth.

[Illustration]

Even after that there was one more tool that had work to do before oil
could be pumped through their pipeline. It is a peculiar gadget that
looks like a bunch of cowboy spurs hooked up with pieces of tin can and
some old plates. The weird contraption is called the go-devil, and it
has the job of traveling, perhaps hundreds of miles, inside the pipe,
pushing out anything that could clog the line. Water pumped into the
line behind the go-devil forces it through the pipe.

In one line, the go-devil brought out chunks of wood, pieces of
rock--and several rabbits, skunks and rattlesnakes that had decided the
pipe would make good headquarters! Now the powerful pumps could go to
work shoving oil through the line.


MINING MACHINERY

Oil pumps today are much better and stronger than the first pumps ever
built, but they are direct descendants of the ones that were invented
for use in English coal mines long ago. In fact, those early pumps were
the great-granddaddies of all modern machines.

[Illustration]

[Illustration]

Coal miners in England had dug so far beneath the surface of the earth
that the shafts and tunnels were in danger of filling up with water.
Neither manpower nor the power of horses hitched to pumps could do the
tremendous job of keeping the mines dry. Something much stronger was
needed. In order to find a new kind of power, inventors began
experimenting with steam. The first workable steam engines were made to
pump out coal mines more than two hundred years ago.

After a while steam engines began to pull trains over rails and drive
ships through the water. They ran threshing machines on farms. Then
inventors used their new knowledge about power to make other kinds of
engines driven by gasoline or electricity or oil.

[Illustration]

At last some of this new machinery began to work its way back into the
mines. Power driven elevators carried the men up and down shafts to
their work. But the miners still did all the coal digging and loading
by hand.

Today many miners use power-driven drills for digging. Mechanical
loaders pick up the loose coal and put it into small cars on the tracks
in the tunnel. A little electric locomotive pulls the cars away to the
elevator which hoists them up above ground.

The most remarkable digger of all is the one you’ll see on the next
page. It rolls along a track deep underground until it comes to the
place where its operator wants to cut coal. He pushes a control, and the
machine’s long neck reaches up. The cutting head, at the end of the
neck, starts biting into the coal. The head does its work much faster
and easier than men with hand tools ever could.

[Illustration]

Outside the mine, machines sort the coal according to size and load it
into railroad cars.

[Illustration]

Unloading machinery empties the cars in many places, too. There’s one
coal yard where a woman, pushing buttons, controls machines that do
everything--unload cars, store the coal according to its size in tall
bins, and load the trucks that will deliver it to customers. This is how
the yard works:

Each railroad car empties its coal in a stream onto a moving belt. The
belt carries the coal to a machine called a giraffe, which works like an
escalator. The giraffe lifts the coal into a tall hopper.

[Illustration]

The woman who runs the coal yard sits in an office with a big window,
where she can look out and see everything that’s going on. When a truck
has backed up to a hopper, ready to load, she pushes a button. Coal
drops down out of the hopper onto another giraffe which lifts it into
the body of the truck. As soon as the truck is filled, push goes a
button and the loading stops.


LOADERS, LIFTERS AND SUCH

Moving belt machines work at other jobs, too. They load sand into trucks
and cargo into ships.

On some piers, huge vacuum cleaners empty ships full of sugar or wheat.
At ports on the Great Lakes, machines reach down into ore-carrying ships
and unload them with great speed. At the end of each of these unloaders
hangs a clamshell bucket. Just above the bucket is a little room where a
man sits and watches what goes on. He signals to the operator, telling
him just where to drop the bucket so it can pick up a mouthful of ore.
The ship can be unloaded by two men who do nothing but signal to each
other and push levers. But usually there are several machines working at
the same time so that the job goes as quickly as possible.

When iron ore has been turned into steel bars or wheels or gears,
another kind of lifter can handle them. This one does its work with a
huge electro-magnet that holds heavy weights when electricity is running
through it. The operator drops the magnet onto the load of iron or steel
that he wants to lift. Then he turns on the electricity which makes the
magnet and the piece of metal stick together. The operator moves the
load wherever it is supposed to go. Then he turns off the electricity.
The magnet lets loose and is ready for another job.


MACHINES FOR LUMBER, TOO

Machines dug and loaded and delivered the coal that keeps your house
warm. Machines helped cut the lumber that went into building your house,
too.

Far out in the woods, power-driven saws sliced quickly through the
trunks of great trees. Caterpillar tractors hauled the logs out along
rough forest trails.

Perhaps the cats, using booms, lifted the logs onto extra-long trailers
behind trucks and started them on the way to the sawmill. Or the cats
may have snaked the logs to a river so they could float downstream to a
sawmill.

[Illustration]

No matter how the logs reached the sawmill, they were put at last onto
belts which pushed them against huge whirling saws. A whole set of saws,
all whining and screaming at once, turned the thick log into boards.
Other machines planed the boards to make them smooth and then cut them
to exactly the right sizes. Finally lift-trucks picked up great piles of
board at once, whizzed them away and hoisted them elevator-fashion into
high stacks.

[Illustration]

[Illustration]


BRAIN POWER

[Illustration]

The operators of most machines sit where they can see what they are
doing, or where they can get signals from helpers. But there is one that
does things in a new way. Its operator just watches television in his
cab. He never sees the parts of his machine at work. Instead, he looks
at the television screen. A television camera on the roof of the
building photographs what is going on below. This is what the eye of the
camera sees: One machine that gathers up pieces of scrap metal and dumps
them into a squeezer; the squeezer that presses the scraps into neat
bundles; a conveyor that loads the bundles into a railroad car.

The operator watches the moving picture. Then he pushes levers that
control the loaders and other levers that send a car on its way when it
is full. The only thing he can’t do is switch on a regular TV program
and watch a show while he works!

[Illustration]

The time may come when people who operate other kinds of machines will
find television helpful in many ways. Meantime, scientists who know how
television works also know how to make the most wonderful machines of
all. Instead of saving muscle-power, these machines save brain-power.
They solve very complicated mathematical problems at lightning speed.
In fact, they are called “thinking machines.” They add, subtract,
multiply, divide and do figuring that many college professors can’t even
do.

Partly for fun, and partly to discover new things, the thinking-machine
experts have also invented mechanical animals. They’ve made turtles that
can walk all around a room without bumping into anything. They’ve made a
little wire-whiskered mechanical mouse that can actually sniff about
until it finds something it is supposed to find--just the way a real
mouse sniffs out a piece of cheese. The machine-mouse even “remembers”
where it went, and it runs straight to its cheese the next time.

The machines you’ve read about in this book are mostly outdoor machines,
operated by one man or a small crew of men. These are only a few of the
marvellous inventions that you can find at work every day. Of course,
there are hundreds and thousands of others in factories, making cloth,
shaping automobile parts, printing books, doing the important work the
world needs done. But, no matter how marvellous and complicated they
are, they will never be as wonderful as the men who have invented them
and built them and used them. When we talk about machines, we’re really
talking about people.


FUNNY NAMES

Some machines resemble animals in the way they look or the things they
do, and so they have animal names. Besides the caterpillar with its
crawler treads and the crane with its long neck, here are some others:

[Illustration]

ALLIGATOR GRAB--a tool used to pick up things that get dropped into oil
well holes.

CAMEL-BACK CRANE--this one has a hump in its boom.

FISHTAIL BIT--a drilling tool which is shaped like a fish’s tail.

KANGAROO PLOW--a plow equipped with strong springs so it can hop over
rocks or tree stumps, instead of getting caught on them.

SHEEP’S FOOT TAMPER--a heavy road roller with spikes that pack earth
down, the way a flock of sheep does.

WORM LOADER--a long screw that twists round and round to push its load
along.




INDEX

airplane duster, 26

asphalt spreader, 65


bailer, 34

baler, automatic, 26-27

beet digger, 42

bit, 69

blower, 28

boom, 9, 49, 51, 55, 74, 85

“box seat,” 22

bucker, 53

bulldozer, 45, 55, 57, 61, 67, 74, 77

bull wheel, 73, 74


cable rig, 72

catcher, 53

caterpillar, 45, 46, 60, 67, 68, 74, 77, 85

cats, 68

cement mixer, 65

chicken picker, 24-25

Chinese drillers, 73-74

chisel plow, 32

clamshell, 49, 84

coal digger, 81

coal loaders, 81

coal mining, 9, 78-83

corn cutter, 25

corn picking machine, 21

corn planter, 19

cotton picker, 37-38

cotton planter, 37

crane, 10, 49-52, 54, 85

crawler tractor, 45

crawlers, 10, 48, 49

crowd shovel, 49

“cub” tractor, 44

cultivator, 21

cutter heads, 15

cutting head, 81

cyclone, 39


derrick, 69

Diesel engine, 47

dipper, 49

“dogging,” 52

dredges, 14-15

driller, 72

driverless plow, 32-35


earth mover, 58

egg machinery, 24

egg sorter, 24

electro-magnet, 84

escalators, 83-84


farm machines, 18-45


giraffe, 83

go-devil, 77-78

gooseneck trailer, 48

grader, 61-64

grass planter, 26


harrow, 18

hay baler, 26-27

hay blower, 67

hay rake, 27

hay stacker, 28-29

heater, 53

hoe, compressed air, 36, 37

“hot-dope gang,” 74

house, 49

house moving, 58


jackhammers, 12

jib, 52

joint, 70


lumbering machinery, 85-86


magnet crane, 84

“making hole,” 72

manure scoop, 24

mechanical mouse, 89

milking machine, 29-32

mining, machinery 78-83

motor grader, 61-64, 67

motor scraper, 57

mowing machine, 26

Muskeg schooner, 69


nut harvester, 41


oil wells, 69-74

ore unloaders, 84

overhead crane, 10


“package job,” 22

piggy-back crane, 10

pile driver, 13

pipelines, 74-78

plow, 17, 18, 32, 33, 34, 35

post-hole digger, 16

potato digger, 42

powder monkey, 60

power shovel, 47-48

pull-shovel, 49

pumps, 78-80


reaper, 22, 42
rig, 70

ripper, 61

rivet gun, 53

rivet man, 53

road building machines, 55-68

rock crusher, 12

rock rake, 60

rotary rig, 72

rotolactor, 30-32

roughnecks, 72


scraper, 61

seed planter, 67

shovel, 9, 47-48, 49

signals, 52, 84, 88

silage blower, 26

skull cracker, 54

snow plow, 45, 67

spraying machines, 38-39

spud, 15

squeezer, 89

steam engines, 80

steam roller, 66

steam shovel, 47-48

suction dredge, 57


tandem roller, 65

tassel picker, 40-41

television, 88, 89

“thinking machines,” 89

tomato planter, 22

tongs, 70

tractor, 17, 18, 44, 45, 58, 61

trailer houses, 69

tree-dozer, 17

tree-shaker, 41

trencher, 74-77

turntable, 51

turtle, 89

two-gang plow, 18


vacuum unloaders, 84


welding crew, 74

well drilling, 69-74

wheat planting machine, 22

windrower, 27

wrecker, 54

[Illustration]

     The author and the artist wish to thank the following for their
     help in making this book possible: Miss Elsie Eaves, Manager,
     Business News Department, _Engineering News-Record_; Margaret
     Gossett; Mr. Harold Spitzer; _The Lamp_, published by the Standard
     Oil Company (New Jersey); the Caterpillar Corp.; the General Motors
     Corp., the New Jersey Bell Telephone Co.; the Florida Land Clearing
     Equipment Co.; the Walker-Gordon Laboratory Co.; the many
     manufacturers of digging, road-building and other specialized
     machines; a bumper crop of tractor and farm implement makers; and
     farmer friends who proudly showed their equipment in action.

                   *       *       *       *       *

$1.50

                           MACHINES AT WORK

                           _By_ Mary Elting

                     _Illustrated by_ Laszlo Roth

There are machines to dig, to hammer, to push--to do every kind of heavy
job and to make work thousands of times easier and faster.

On farms, in the mines, in cities where huge buildings are built and out
in the woods where powerdriven saws slice through great trees, many
kinds of special machines do many kinds of remarkable jobs.

Can you imagine a giant shovel so huge that it took 45 freight cars to
haul it from factory to mine? Do you know that there is a machine that
plucks the feathers off chickens, ones that pick corn, dig potatoes?
Inventors of machines work on everything--they even had fun making a
mechanical mouse that can sniff about until it finds a piece of “cheese”
and then “remember” and run straight to it next time!

As marvelous and complicated as all these machines are, the author
points out that no inventions will ever be as wonderful as the men who
invented them--and the men who make them work.

You will find this book an exciting companion to TRAINS AT WORK, SHIPS
AT WORK, TRUCKS AT WORK.

                         Garden City Books

                        Garden City, New York

                    *       *       *       *       *

                            TRUCKS AT WORK

                           _By_ Mary Elting

                    _Illustrated by_ Ursula Koering

This is a book about the sort of trucks that you see every day, as well
as the most wonderful out-of-the-way trucks that you may not yet have
discovered. It tells of city trucks, with their endless and fascinating
cargoes, trucks that help on the farm, and trucks that rumble along the
country roads hauling anything from horse-stables to houses.

The author also tells you how the drivers arrange their routes, and how
they learned to foil hijackers--and the pictures will tell you just as
much as the text. You can see how a truck is loaded so that nothing gets
smashed or spoilt; and how a truck Roadeo tests the skill of the men who
drive the huge trailer rigs. There is lots of fun here besides useful
information.

                         Garden City Books

                        Garden City, New York

                  *       *       *       *       *

                        FOUR INFORMATIVE BOOKS

                    [Illustration: TRUCKS AT WORK]

Every kind of truck.... loads they haul, the way the drivers.... arrange
 their routes, how to foil.... hijackers and how a truck Roadeo.... is
       run are vividly presented in story and colorful pictures.

                    _ILLUSTRATED BY URSULA KOERING_

                     [Illustration: SHIPS AT WORK]

Freighters and tankers, tugs and giant ocean liners are shown in action.
 Vivid text and colorful pictures take you right through the world of
         ships and show you the life of the men who sail them.

                  _ILLUSTRATED BY MANNING DE V. LEE_

                    [Illustration: TRAINS AT WORK]

 Many different kinds of locomotives, trains and special cars are all
shown in action. You can see the different jobs engineers, brakemen and
 signalmen do. Colorful pictures show railroading realistically and in
                             full detail.

                  _ILLUSTRATED BY DAVID LYLE MILLARD_


                           MACHINES AT WORK

Machines that dig, hammer, push--in non-technical language, the author
 explains the fascinating things they do, how they work and something
 about the men who run them. Full-color pictures show each machine in
                                action.

                     _ILLUSTRATED BY LASZLO ROTH_

                                  ALL
                                  BY
                                 MARY
                                ELTING


               GARDEN CITY BOOKS--GARDEN CITY--NEW YORK